BACKGROUND OF THE INVENTION
[0001] The present invention relates to novel phenylalkyl-2,3-dihydrobenzofurans and the
corresponding di- hydrobenzopyrans useful as anti-inflammatory agents. A group of
benzyldihydrobenzofurans have been disclosed in U.S. patent 4,435,422 as effective
diuretic agents. However, this patent does not disclose the novel compounds of the
present invention, nor does it disclose the anti-inflammatory activity of the compounds
of the present invention.
[0002] The novel compounds are effective in vitro as both leukotriene and prostaglandin
synthesis inhibitors in the peritoneal macrophage assay and the polymorphonuclear
leukocyte assay. They are also potent lipoxygenase inhibitors. Furthermore, they are
found to be active in vivo in the topical mouse ear assay and the U.V. erythema assay
as topical anti-inflammatory agents.
[0003] Recent studies demonstrated that macrophages and PMNs participate in the development
and progression of chronic inflammatory diseases such as rheumatoid arthritis. During
the progression of inflammatory conditions, there is generally an appearance and/or
presence of macrophages and lymphocytes, especially macrophages and polymorphonuclear
leukocytes. Macrophages are known to secrete various products in response to inflammatory
stimuli. For example:
1) Neutral proteinases - the destructive peptide bond cleaving enzyme which has been
shown to be directly involved in rheumatoid cartilage destruction; and
2) Prostaglandins (PG) (e.g., E2 and 12 by mouse peritoneal macrophages) and other arachidonic acid derivatives derived from
both the cyclooxygenase and the lipoxygenase pathways.
[0004] These archidonic acid oxygenation products have been identified as the critical mediators
of various acute inflammatory conditions.
[0005] Accordingly, pharmacological agents which are capable of inhibiting the formation
of, the release of a mediator from, or the function of macrophages or polymorphonuclear
leukocytes may also be effective agents in the treatment of rheumatoid arthritis,
emphysema, bronchial inflammation, asthma, osteoarthritis, acute respiratory distress
syndrome, shock syndromes, e.g., endotoxin shock syndrome, spondylitis, lupus, gout,
psoriasis, pain, eye inflammation, and other inflammatory diseases.
[0006] Regarding the topical mouse ear assay, it has been previously established that classical
nonsteroidal anti-flammatory agents such as indomethacin and steroidal anti-inflammatory
agents such as dexamethasone are active in this assay.
[0007] With respect to the U.V. erythema assay, it has been shown previously that the U.V.
erythema condition is partially the result of a local release of prostaglandins derived
oxidatively from arachidonic acid by the action of PG synthetases, e.g., cyclooxygenase.
Therefore, pharmacological agents which inhibit the erythema are generally considered
to be active topical anti-inflammatory agents.
[0008] Furthermore, anit-inflammatory agents which are not significantly systemically active
are advantageous in the sense that they are not subject to the adverse effects, e.g.,
gastrointestinal ulcerations and bleeding that often plagued users of systemic NSAIDs
(non-steroidal anti-inflammatory agents). Accordingly, an object of this invention
is to provide novel phenylalkyldihydrobenzofuran derivatives and analogs as topical
anti-inflammatory agents. These agents are useful in the treatment of dermal inflammatory
conditions and pruritus such as sunburn, erythema, eczema, contact dermatitis, allergic
dermatitis, psoriasis, and other skin diseases. They are also useful for topical application
to prevent or treat peri- dontal diseases or to treat ocular inflammation.
[0009] Another object of this invention is to provide appropriate processes for the preparation
of the subject novel compounds.
[0010] Still a further object of the present invention is to provide a pharmaceutically
acceptable composition containing an effective amount of the active compound for the
treatment of various inflammatory diseases especially those involving dermatological
conditions.
[0011] Finally, it is the object of this invention to develop a method of treating inflammation
especially dermal inflammation via the administration of a therapeutically effective
amount of the novel compounds or pharmaceutically acceptable compositions thereof
to a mammalian species in need of such treatement.
DETAILED DESCRIPTION OF THE INVENTION
A. Scope of the Invention
[0012] This invention relates to novel compounds of formula (I):

or a pharmaceutically acceptable salt thereof, wherein
m is 1 to 4;
n is 2 or 3;
r is 1 to 3;
A is
[0013] (a) phenyl substituted with (R
1)
q wherein q is an integer of 1 to 5 and when there are more than one R
l, R
1 can be the same or different from each other and is
(1) hydrogen;
(2) halo especially fluoro, chloro or bromo;
(3) C1-6 alkoxy, e.g., methoxy, ethoxy, isopropoxy, t-butoxy or cyclohexyloxy, or -OCH2O-;
(4) C1-6 alkylthio, or C1-6haloalkylthio e.g., methylthio, ethylthio, trifluoromethylthio or cyclohexylthio;
(5) C1-6 alkyl sulfinyl, e.g., methyl sulfinyl, i-propyl sulfinyl, and cyclopentyl sulfinyl;
(6) C1-6 alkyl sulfonyl such as methyl sulfonyl, ethyl sulfonyl and n-butyl sulfonyl;
(7) phenyl C1-6 alkoxy such as benzyloxy;
(8) C1-6 alkyl such as methyl, ethyl, propyl, t-butyl, pentyl, benzyl, cyclopropyl, cyclopentyl
or cyclohexyl;
(9) C2-6 alkenyl, for example, vinyl, allyl, and buten-2-yl;
(10) C1-6alkanoyl such as formyl, acetyl or i-propanoyl;
(11) C1-6haloalkyl such as trifluoromethyl;
(12) -COOH;
(13) phenyl, 4-methoxyphenyl, 2,4-difluorophenyl or 3-chlorophenyl;
(14) phenoxy;
(15) cyano;
(16) hydroxy C1-3alkyl such as -CH20H, CH3-CH(OH)-;
(17) haloC1-6 alkanoyl e.g. CFsCO;
(18) heteroaryl as defined below;
(19) C1-6 alkanoyloxy especially acetyloxy;
(20) hydroxy; or
(21) C1-6 alkanoyl- or haloC1-6 alkanoyl-C1-6 alkyl;
[0014] (b) unsubstituted or substituted heteroaryl, for example:
(1) thienyl;
(2) benzothienyl;
(3) furyl;
(4) benzofuryl;
(5) pyrryl;
(6) indolyl;
(7) thiazolyl;
(8) benzothiazolyl;
(9) thiadiazolyl;
(10) benzothiadiazolyl;
(11) quinolyl;
(12) isoquinolyl;
(13) pyridyl;
(14) pyrazinyl;
(15) tetrazolyl;
(16) triazolyl; or
(17) imidazolyl;
the heteroaryl above can be substituted with one or more of R
1, e.g., C
1-6alkyl, C
1-6alkanoyl, C
1-shaloalkyl, halo, cyano, or hydroxy C
1-3alkyl; R and R2 independently are R
1.
[0015] In a preferred embodiment of this invention, A is phenyl substituted with (R
1)
q wherein q is 1 or 2 and R
1 is
(a) hydrogen;
(b) C1-salkoxy;
(c) halo;
(d) haloC1-6alkyl,
(e) C1-6alkanoyl;
(f) hydroxyC1-6 alkyl;
(g) hydroxy; or
(h) CN;
[0016] R is R
1 and R can be the same as or different from R
1;
R2 is H;
nis 2 or 3;
m is 2 to 4; and
r is 1.
[0017] In the even more preferred embodiment of the present invention, the compounds are
of the following formulae:

wherein R and R
1 are C
1-6alkanoyl or hydroxyC
1-3alkyl and wherein R and R
1 can be same or different.
B. Preparation of the Compounds within the Scope of the Invention:
[0019] The procedures for preparing the starting materials such as cinnamylphenols are known
and their preparations are similar to those disclosed in U.S. Patents 3,745,222; 3,775,540;
3,777,039; 3,865,748; 3,936,393; 3,951,820; and 4,105,698.
C. Utility of the Subject Compounds of the Invention
[0020] This invention also relates to a method of treating inflammation especially topical
inflammation in patients in need of such treatment. Generally, a sufficient amount
of a compound of formula (I) or a pharmaceutical composition thereof, is administered
to the patient as the active constituent.
[0021] The topical mouse ear assay (TME) was used to evaluate the novel compounds of the
present invention for its effect on inflammatory responses elicited by topically applied
phorbol myristate acetate (PMA) or topically applied archidonic acid (AA). The inflammatory
responses may be in the form of edema (measured by wet weight); vascular permeability
(measured by 1251-BSA accumulation); or PMN in filtration (measured by myeloperoxidase
activity). A protocol of the assay and some results derived therefrom are summarized
below.
Topical Mouse Ear Assay
[0022] Method: The right ears of mice (5 mice per group) were treated topically with either
5 µl PMA or 1000 µg AA alone or with the test compound in 25 µl of vehicle. The vehicle
was water/pyridine/acetone (1:2:97). A control group of mice received the vehicle
only. The mice were allowed food and water ad libitum during the treatment period;
2 hours for AA and 4 hours for PMA. The mice were sacrificed by cervical dislocation
and a 6 mm diameter disc of tissue punched from both the treated and untreated ears.
The tissue biopsies were immediately weighed and the weight increase of the treated
ear relative to the weight of the untreated ear determined.
[0023] For the determination of vascular permeability, 1 µM
1251-bovine serum albumin (1251-BSA) was administered in 0.5 ml phosphate buffered saline
15 min prior to the topical application. At the termination of the experiment, the
amount of radioactivity in both the treated and untreated ear biopsies was determined
and the increased amount of radioactivity in the treated tissue relative to the amount
of radioactive in the untreated tissue determined.
[0024] As a measure of PMN infiltration, the amount of myeloperoxidase (MPO) activity in
the same tissues was determined. The tissue biopsies were homogenized into 1 ml 0.5%
hexadecyltrimethylammonium bromide and centrifuged for 45 min. at 1200 x g. Aliquots
40 µl, of the supernatant phases were assayed for MPO activity by a colorimetric method
devised by H. Dougherty for automated Titertek analysis. The MPO activity is expressed
as the OD
450 of the treated ear homogenate minus the OD
450 of the non- treated ear homogenate.
[0025] All of the data are expressed as the mean ± SEM, N=5 mice/group. The results are
summarized below in Table I.

[0026] For treatment of inflammation, fever or pain, the compounds of the invention are
administered topically, by inhalation spray or rectally in dosage unit formulations
containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants
and vehicles.
[0027] The pharmaceutical composition containing the active ingredient may be in a form
suitable for topical use, for example, aqueous or oily solutions or suspensions, dispersible
powders or granules, tinctures, topical aerosol emulsions, creams, ointments, jellies,
suppositories or the like. Compositions intended for topical use may be prepared according
to any method known to the art for the manufacture of pharmaceutical compositions
and such compositions may contain one or more active compounds.
[0028] Aqueous suspensions contain the active materials in admixture with excipients suitable
for the manufacture of aqueous suspensions. Such excipients are suspending agents,
for example sodium carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose,
sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; dispersing or
wetting agents may be a naturally-occurring phos- phatide, for example lecithin, or
condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene
stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols,
for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide
with partial esters derived from fatty acids and a hexitol such as polyoxyethylene
sorbitol monooleate, or condensation products of ethylene oxide with partial esters
derived from fatty acids and hexitol anhydrides, for example polyoxyethylene sorbitan
monooelate. The said aqueous suspensions may also contain one or more preservatives,
for example, ethyl, or n-propyl p-hydroxybenzoate.
[0029] Oily suspensions may be formulated by suspending the active ingredient in a vegetable
oil, for example, arachis oil, olive oil, sesame oil or coconut oil, or in a mineral
oil such as liquid paraffin. the oily suspensions may contain a thickening agent,
for example, beeswax, hard paraffin or cetyl alcohol. These compositions may be preserved
by the addition of an antioxidant such as ascorbic acid.
[0030] Dispersible powders and granules suitable for preparation of an aqueous suspension
by the addition of water provide the active ingredient in admixture with a dispersing
or wetting agent, suspending agent and one or more preservatives. Suitable dispersing
or wetting agents and suspending agents are exemplified by those already mentioned
above.
[0031] The pharmaceutical compositions of the invention may also be in the form of oil-in-water
emulsions. The oily phase may be a vegetable oil, for example, olive oil or arachis
oils, or a mineral oil, for example, liquid paraffin or mixtures of these. Suitable
emulsifying agents may be naturally-occurring gums, for example, gum acacia or gum
tragacanth, naturally-occurring phosphatides, for example, soy bean lecithin, and
esters or partial esters derived from fatty acids and hexitol anhydrides, for example,
sorbitan monooleate, and condensation products of the said partial esters with ethylene
oxide, for example, polyoxyethylene sorbitan monooleate.
[0032] An ointment containing the pharmaceutical compositions of the present invention may
be prepared, among other methods known in the art, by combining the active ingredient
with a medium consisting of a glycol, a lower alkanol, and water; a gelling agent;
and optionally an adjuvant such as diisopropyl adipate, diethyl sebacate, ethyl caproate
and ethyl laurate. Suitable glycols include propylene glycol, butylene glycol, polyethylene
glycol and the like. Generally, a caboxyvinyl polymer preneutralized with an organic
amine such as diisopropyl amine and triethylamine, or a cellulose, e.g., hydroxyethyl
cellulose, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, is
used as the gelling agent.
[0033] The compounds of the invention may also be administered in the form of suppositories
for rectal administration of the drug. These compositions can be prepared by mixing
the drug with a suitable non-irritating excipient which is solid at ordinary temperatures
but liquid at the rectal temperature and will therefore melt in the rectum to release
the drug. Such materials are cocoa butter and polyethylene glycols. Dosage levels
of the order to 0.1 mg to 140 mg per kilogram of body weight per day are useful in
the treatment of the above-indicated conditions (5 mg to 7 gms per patient per day).
For example, inflammation is effectively treated by the administration from about
0.5 to 50 mg of the compound per kilogram of body weight per day (25 mg to 5 gms per
patient per day). Advantageously, from about 2 mg to about 20 mg per kilogram of body
weight per daily dosage produces highly effective results (50 mg to 1 gm per patient
per day).
[0034] The amount of active ingredient that may be combined with the carrier materials to
produce a single dosage form will vary depending upon the host treated and the particular
mode of administration. Dosage unit forms will generally contain between from about
25 mg to about 1 g of active ingredient.
[0035] Particularly, for use in treatment of ophthalmic conditions including those associated
with elevated intraocular pressure such as glaucoma or other inflammation in the eye,
the active compound can be administered topically or systemically when it is appropriate.
The dose administered can be from as little as 0.1 to 25 mg or more per day, singly,
or preferably on a 2 to 4 dose per day regimen although a single dose per day is satisfactory.
[0036] When given systemically, the drug can be given by any route, although the oral route
is preferred. In oral administration the drug can be employed in any of the usual
dosage forms such as tablets or capsules, either in a contemporaneous delivery or
sustained release form. Any number of the usual excipients or tableting aids can likewise
be included.
[0037] When given by the topical route, the active drug or an ophthalmologically acceptable
salt thereof such as the sodium or potassium salt is formulated into an ophthalmic
preparation. In such formulations, from 0.1 % to 15% by weight can be employed. The
objective is to administer a dose of from 0.1 to 10 mg per eye per day to the patient,
with treatment continuing so long as the condition persists.
[0038] Thus, in an ophthalmic solution, insert, ointment or suspension for topical delivery,
or a tablet, intramuscular, or intravenous composition for systemic delivery, the
active medicament or an equivalent amount of a salt thereof is employed, the remainder
being carrier, excipients, preservatives and the like as are customarily used in such
compositions.
[0039] The active drugs of this invention are most suitably administered in the form of
opthalmic pharmaceutical compositions adapted for topical administration to the eye
such as a suspension, ointment, or as a solid insert. Formulations of these compounds
may contain from 0.01 to 15% and especially 0.5% to 2% of medicament. Higher dosages
as, for example, about 10%, or lower dosages can be employed provided the dose is
effective in reducing or controlling elevated intraocular pressure. As a unit dosage
from between 0.001 to 10.0 mg, preferably .005 to 2.0 mg, and especially 0.1 to 1.0
mg of the compound is generally applied to the human eye, generally on a daily basis
in single or divided doses so long as the condition being treated exists.
[0040] As with all medications, dosage requirements are variable and must be individualized
on the basis of the disease and the response of the patient.
[0041] The pharmaceutical preparation which contains the active compound may be conveniently
admixed with a non-toxic pharmaceutical organic carrier, or with a non-toxic pharmaceutical
inorganic carrier. Typical of pharmaceutically acceptable carriers are, for example,
water, mixtures of water and water-miscible solvents such as lower alkanols or aralkanols,
vegetable oils, polyalkylene glycols, petroleum based jelly, ethyl cellulose, ethyl
oleate, carboxymethylcellulose, polyvinylpyrrolidone, isopropyl myristate and other
conventionally employed acceptable carriers. The pharmaceutical preparation may also
contain non-toxic auxiliary substances such as emulsifying, preserving, wetting agents,
bodying agents and the like, as for example, polyethylene glycols 200, 300, 400 and
600, carbowaxes 1,000, 1,500, 4,000, 6,000 and 10,000, antibacterial components such
as quaternary ammonium compounds, phenylmercuric salts known to have cold sterilizing
properties and which are non-injurious in use, thimerosal, methyl and propyl paraben,
benzyl alcohol, phenyl ethanol, buffering ingredients such as sodium chloride, sodium
borate, sodium acetates, gluconate buffers, and other conventional ingredients such
as sorbitan monolaurate, triethanolamine oleate, polyoxyethylene sorbitan monopalmitate,
dioctyl sodium sulfosuccinate, monothioglycerol, thiosorbitol, ethylenediamine tetraacetic
acid, and the like. Additionally, suitable ophthalmic vehicles can be used as carrier
media for the present purpose including conventional phosphate buffer vehicle systems,
isotonic boric acid vehicles, isotonic sodium chloride vehicles, isotonic sodium borate
vehicle and the like.
[0042] The pharmaceutical preparation may also be in the form of a solid insert such as
one which after dispensing the drug remains essentially intact, or a biodegradable
insert that either is soluble in lacrimal fluids, or otherwise disintegrates.
[0043] The following examples of ophthalmic formulations are given by way of illustration.

[0044] Compound A, phosphate buffer salts, and benzalkonium chloride are added to and dissolved
in water. The pH of the composition is adjusted to 6.8 and diluted to volume. The
composition is rendered sterile by ionizing radiation.
EXAMPLE B
[0045]
A Compound of formula (I) 5 mg.
petrolatum q.s. ad. 1 gram
The active compound and the petrolatum are aseptically combined.
EXAMPLE C
[0046]
A Compound of formula (I) 1 mg.
Hydroxypropylcellulose q.s. 12 mg.
[0047] Ophthalmic inserts are manufactured from compression molded films which are prepared
on a Carver Press by subjecting the powdered mixture of the above ingredients to a
compressional force of 12,000 lbs. (gauge) at 300
°F for one to four minutes. The film is cooled under pressure by having cold water
circulate in the platen. Ophthalmic inserts are then individually cut from the film
with a rod-shaped punch. Each insert is placed into a vial, which is then placed in
a humidity cabinet (88% R.H. at 30
°C) for two to four days. After removal from the humidity cabinet, the vials are stoppered
and then capped. The vials containing the hydrate insert are then autoclaved at 250°F
for % hour.
EXAMPLE D
[0048]
A Compound of formula (I) 1 mg.
Hydroxypropyl cellulose q.s. ad. 12 mg.
[0049] Ophthalmic inserts are manufactured from a solvent cast film prepared by making a
viscous solution of the powdered ingredients listed above using methanol as the solvent.
The solution is placed on a Teflon plate and allowed to dry at ambient conditions.
After drying, the film is placed in an 88% R. H. cabinet until it is pliable. Appropriately
sized inserts are cut from the film.
EXAMPLE E
[0050]
A compound of formula (I) 1 mg.
Hydroxypropylmethyl cellulose q.s. ad. 12 mg.
[0051] Ophthalmic inserts are manufactured from a solvent cast film which is prepared by
making a viscous solution of the powdered blend of the above ingredients using a methanol/water
solvent system (10 ml. methanol is added to 2.5 g. of the powdered blend, to which
11 ml. of water (in three divided portions) is added). The solution is placed on a
Teflon plate and allowed to dry at ambient conditions. After drying, the film is placed
in an 88% R. H. cabinet until it is pliable. Appropriately sized inserts are then
cut from the film.
EXAMPLE F
[0052]
A Compound of formula (I) 1 mg.
Hydroxypropylmethyl cellulose q.s. ad. 12 mg.
[0053] Ophthalmic inserts are manufactured from compression molded films which are prepared
on a Carver Press by subjecting the powdered mixture of the above ingredients to a
compressional force of 12,000 lbs. (gauge) at 350
°F for one minute. The film is cooled under pressure by having cold water circulate
in the platen. Ophthalmic inserts are then individually cut from the film with a punch.
Each insert is placed into a vial, which is then placed in a humidity cabinet (88%
R. H. at 30
°C) for two to four days. After removal from the humidity cabinet, the vials are stoppered
and then capped. The vials containing the hydrated insert are then autoclaved at 250
°F for one-half hour.
[0054] It is highly preferred that the solid inserts of this invention are available for
use by the patient in a pathogen free condition. Thus, it is preferred to sterilize
the inserts and to insure against recontamination, the sterilization is preferably
conducted after packaging. The best mode of sterilizing is to employ ionizing radiation
including radiation emanating from Cobalt 60 or high energy electron beams.
EXAMPLE G
[0055] The following materials are mixed in a 1250 ml bottle: 24 g of Compound A which is
a sufficient amount of medicament to result in a concentration of 10 mg per ml in
the final samples, allowing for previously established 3.0% average; 0.4 g sodium
bisulfite, 12 g NaCl, and 28 ml water (at 180
°F). This mixture, (I), is autoclaved for 30 minutes at 121 °C under 15 psi. Separately,
3 g of hydroxyethylcellulose in 720 ml of water (II) and 0.4 g of lecithin in 80 ml
of water (III) were autoclaved for 30 minutes at 121°C. Then, (III) is admixed with
(I) for 2 hours, and the resultant mixture poured into (II). Another mixture (IV)
is prepared from 20 g of sorbitol, 2.36 ml of benzalkonium chloride, 10 g of disodium
edetate, and water to give a final solution volume of 900 ml. Then, (IV) is added
to the mixture of (I), (II), and (III) in sufficient quantity to give 1.8 I. overall.
The 1.8 I. mixture of I, II, III, and IV is then taken and homogenized using a homogenizer
at 200 psig. Stock solutions are then prepared for polyoxyethylene (20) sorbitan monooleate
by dissolving 3 g of the material in 100 ml of water, and of benzyl alcohol/¡3-phenyl-ethyl
alcohol by admixing 50 ml of each alcohol. Varying quantities of the two stock solutions
are then added to four 90 ml aliquots of the homogenized mixture of (I), (II), (III),
and (IV) prepared as described above, together with sufficient water to give a total
of 100 ml of each of four different samples.
[0056] Other formulations, in an oil vehicle and an ointment are exemplified in the following
examples.
EXAMPLE H
[0057]
Solution Composition
Compound B 0.1 mg
Peanut oil q.s. ad. 0.10 mg.
The solution is rendered sterile by filtration through a sterilizing filter.
EXAMPLE I
[0058]
Compound A 0.5 mg.
Petrolatum q.s. ad. 1 gram
The compound and the petrolatum are aseptically combined.
[0059] It will be understood, however, that the specific dose level for any particular patient
will depend upon a variety of factors including the activity of the specific compound
employed, the age, body weight, general health, sex, diet, time of administration,
route of administration, rate of excretion, drug combination and the severity of the
particular disease undergoing therapy.
[0060] Set forth below are some illustrative topical formulations containing a selected
active compound of the instant invention.
Formulation Number 1 - Solution
[0061] Distilled water qs to 100%
[0062] Procedure: Dissolve compound (A) in enough water to make 100%. Filter the solution.
Apply to the affected area.
[0063] Formulation Number 2 - Tincture
[0064] Alcohol U.S.P. - 50% Water qs to 100%
[0065] Procedure: Dissolve compound (A) in the alcohol. Add sufficient water to make 100%.
Filter and apply to affected area.
Formulation Number 3 - Topical Aerosol
[0066] Alcohol U.S.P. - 5%
[0067] Isopropylmyristate - 5%
[0068] Conventional halogenated hydrocarbon propellant qs 100% e.g., Freon 11 (trichlorofluoromethane),
Freon 12 (dichlorodifluoromethane), Freon 14 (carbon tetrafluoride), Freon C 318 (Octafluorocyclobutane),
Freon 114 (Cryofluorane), etc.
[0069] Procedure: Dissolve Compound (A) in the alcohol and isopropylmyristate. Add sufficient
halogenated propellant and introduce into conventional aerosol containers either by
pressure or by cold filling. Apply to affected area.
Formulation Number 4 - Ointment
[0070] Petrolatum U.S.P. qs to 100%
[0071] Procedure: Heat the petrolatum to 60
°C. Add compound (A) and stir until thoroughly dispersed. Cool to room temperature.
Apply to affected area.
[0072] Set forth below are some illustrative examples for the preparation of the compounds
of the present invention:
EXAMPLE 1
6-(3-(2-hydroxymethyl-phenyl)propyl)-5-hydroxy-2,3-dihydrobenzofuran
[0073] 6-(3-(2-hydroxymethylphenyl)-trans-prop-2-enyl)-5-hydroxy-2,3-dihydrobenzofuran (2.82
g; 0.01 moles) was dissolved in acetic acid (35 ml) and ethyl alcohol (10 ml) and
hydrogenated at 40 psi at room temperature using Pt0
2 (0.30 g) as a catalyst. The reduction was complete in approximately 3 minutes with
a slight exotherm. The catalyst was removed via suction filtration through a bed of
celite. The bed was washed with ethyl alcohol (2 x 10 ml) and the filtrate was relieved
of solvent in vacuo to afford a crude gum. The gum was dissolved in ethyl ether (50
ml) and was washed sequentially with brine (2 x 50 ml) and saturated NaHC0
3 solution (2 x 50 ml). The organic layer was dried over MgS0
4, filtered, and the filtrate evaporated in vacuo to yield a crude solid. Recrystallization
from ethyl acetate/n-hexane produced 6-(3-(2-hydroxymethyl-phenyl)-propyl)-5-hydroxy-2,3-dihydrobenzofuran
as white needles (1.4 g, 49%, m.p. 110-111.5°C).
Calc'd for C18H20O3: C, 76.03; H, 7.09;
Found: C, 75.84; H, 7.12.
EXAMPLE 2
6-(3-(4-acetyl-phenyl)-propyl)-5-hydroxy-2,3-dihydrobenzofuran
[0074] An isomeric mixture (1:1) of 6-(3-(4-acetylphenyl)-propen-2 or 1-yl)-5-hydroxy-2,3-dihydrobenzofuran
(740 mg, 2.5 mmoles) was hydrogenated at 40 psi in acetic acid (10 ml)/ethyl alcohol
(20 mt)/Pt0
2 (100 mg) until the reduction of the double bond was complete. The catalyst was removed
via suction filtration through a bed of celite, and the filter cake washed with ethyl
alcohol. The filtrate was concentrated in vacuo to afford a crude oil. The oil was
partitioned in Et
2O (25 ml)/H
20 (20 ml) and a sufficient amount of sodium bicarbonate powder was added to neutralize
any residual acetic acid. The layers were separated and the organic phase washed with
saturated NaHC0
3 solution (1 x 20 ml) and then brine (2 x 20 ml).
[0075] The ether layer ws dried over MgS0
4, filtered and the filtrate evaporated in vacuo to produce a crude gum. High performance
liquid chromatography (HPLC) using on EtOAc/hexane (30%:70%) mobile phase on silica
gel was used to separate the title compound from its 1-hydroxyethyl analogs resulting
from the reduction of the acetyl group. The isolated product was recrystallized from
EtOAc/n-hexane to afford phenylalkyl-2,3-dihydrobenzofurans and analogs useful as
anti-inflammatory agents as white crystals. m.p. 125-126.5
°C.
Calc'd for C19H20O3: C, 77.00; H, 6.8;
Found: C, 77.07; H, 6.85.
Similarly, HPLC fractions containing the 1-hydroxyethyl analog were recrystallized
to afford 6-(3-(4-(1-hydroxyethyl)-phenyl)-propyl)-5-hydroxy-2,3-dihydrobenzofuran,
m.p. 104-105°C.
Calc'd for C19H22O3: C, 76.48; H, 7.43,
Found: C, 76.32; H, 7.45.
EXAMPLE 3
6-(2-(1-methyl-imidazol-2-yl)ethyl)-5-hydroxy-2,3-dihydrobenzofuran
Step A: Preparation of 5-benzyloxy-2,3-dihydrobenzofuran-6-carboxaldehyde
[0076] A 2-liter, 3-neck flask equipped with a nitrogen inlet, internal thermometer, mechanical
stirrer, and reflux condenser was charged with 5-hydroxy-2,3-dihydrobenzofuran-6-carboxaldehyde
(50.00 g; 0.30 moles), benzylbromide (38.6 ml, 0.34 moles), and crushed anhydrous
K
2C0
3 (165.84 g, 1.20 moles). The reaction mixture was refluxed for 16 hours, cooled to
room temperature and suction filtered. The filtrate was concentrated in vacuo to afford
a yellow solid. The solid was dissolved in methylene chloride (600 ml) and washed
sequentially with 0.5 N sodium hydroxide solution (3 x 250 ml) and brine (2 x 250
ml). The organic phase was dried over MgS0
4, suction filtered, and the filtrate concentrated in vacuo to yield a crude solid
(85 g). The solid was dissolved in methylene chloride (300 ml)/n-hexane (200 ml),
treated with charcoal and suction filtered through a bed of celite. The filtrate was
evaporated in vacuo to approximately 300 ml and slowly cooled to 0
°C to produce yellowish flat needles (60 g, 78%).
Step B: Preparation of 5-benzyloxy-6-hydroxymethyl-2,3-dihydrobenzofuran
[0077] A flamed dried, N
2 purged 1-liter, 3-neck flask equipped with a dropping funnel, mechanical stirrer,
and thermometer was charged with 5-benzyloxy-2,3-dihydrobenzofuran-6-carboxaldehyde
(30.00 g, 0.12 moles) and anhydrous toluene (150 ml). The resultant yellow solution
was cooled to -65
°C and with efficient stirring a diisobutylaluminum hydride solution in toluene (77
ml of a 25 wt.% solution) was added dropwise over 30 minutes. Upon complete addition,
the reaction mixture was allowed to warm to room temperature and stirred 1 hour more.
The reaction mixture was poured slowly into 2 N HCI (300 ml) and crushed ice (400
ml) with rapid stirring. The quenched mixture was extracted sequentially with Et
20 (2 x 300 ml) and EtOAC (2 x 200 ml). The combined organic layers were washed with
brine (2 x 300 ml), dried over MgS0
4, filtered, and the filtrate concentrated in vacuo to afford 5-benzyloxy-6-hydroxymethyl-2,3-dihydrobenzofuran
as a white precipitate (30.0 g, 97.5%).
Step C: Preparation of 5-benzyloxy-6-(methanesulfonyloxymethyl)-2,3-dihydrobenzofuran
[0078] A flame dried 1-liter, 3-neck flask fitted with a dropping funnel, mechanical stirrer,
N
2 inlet, and an internal thermometer was charged with 5-benzyloxy-6-hydroxymethyl-2,3-dihydrobenzofuran
(28.90 g, 0.11 moles), methylene chloride (250 ml) and triethylamine (16 ml, 0.11
moles). The reaction mixture was chilled to 10
°C and methanesulfonyl chloride (8.9 ml, 0.11 mole) was added dropwise, while maintaining
an internal reaction temperature of 10
°C. The resultant yellow-green mixture was warmed to room temperature and stirred for
15 hours. Water (100 ml) was added to the reaction, the layers partitioned and separated.
The organic phase was washed sequentially with saturated sodium bicarbonate solution
(2 x 100 ml) and brine (1 x 100 ml) to remove some greenish color. The yellow organic
layer was dried over Mg-S0
4, suction filtered and the filtrate concentrated in vacuo to afford 5-benzyloxy-6-methanesulfonyl-
oxymethyl)-2,3-dihydrobenzofuran, a yellow precipitate (33.0 g, 88%). The crude product
was used in the next step without further purification which was not necessary for
the subsequent reaction.
Step D: Preparation of 5-benzyloxy-6-iodomethyl-2,3,-dihydrobenzofuran
[0079] A flame dried, N
2 purged 1-liter, 3-neck round bottom flask equipped with an internal thermometer and
mechanical stirrer was charged with 5-benzyloxy-6-(methanesulfonyloxymethyl)-2,3-dihydrobenzofuran
(30.60 g, 0.10 moles) and anhydrous acetone (250 ml). The resultant solution was cooled
to 0
°C and with efficient stirring sodium iodide (59.90 g, 0.40 moles) in acetone (150
ml) was added in one portion. The reaction mixture was stirred at room temperature
for 72 hours and then suction filtered through a bed of celite. The filtrate was concentrated
in vacuo to afford the crude product. This was dissolved in ethyl ether (400 ml) and
water (200 ml), the layers partitioned, and separated. The organic phase was washed
with saturated NaHS0
3 solution (2 x 200 ml) and water (1 x 200 ml), dried over MgS0
4, suction filtered, and the filtrate concentrated in vacuo to yield 5-benzyloxy-6-iodomethyl-2,3-dihydrobenzofuran
as a yellow solid (33.0 g, 98%).
Step E: Preparation of 5-benzyloxy-2,3-dihydrobenzofuran-6-yl methenyltriphenylphosphonium
iodide
[0080] A flame dried 1-liter, 3-neck flask fitted with a mechanical stirrer, nitrogen inlet,
reflux condenser and internal thermometer was charged with 5-benzyioxy-6-iodomethy)-2,3-dihydrobenzofuran
(25.0 g, 0.7 moles) and anhydrous benzene (250 ml). With efficient stirring, to this
solution was added, dropwise, a solution of triphenylphosphine (18.4 g, 0.7 moles)
in benzene (100 ml). Upon complete addition, the reaction mixture was refluxed for
hour, whereupon a solution formed. This solution was cooled to 0
°C and fine white precipitate formed which was isolated by suction filtration. The
filter cake was washed with ethyl ether and dried in a vacuum oven under a nitrogen
purge. The phosphonium salt was of sufficient purity for the next reaction (41.0 g,
96.0 %).
Step F: Preparation of cis- and trans-isomers of 1-(5-benzyloxy-2,3-dihydrobenzofuran-6-yl)-2-(1-methyl-imidazol-2-yl)ethene
[0081] A flame dried, N
2 purged, 100 ml round bottom flask equipped with a dropping funnel, thermometer and
magnetic stirrer was charged with 5-(benzyloxy)-2,3-dihydrobenzofuran-6-yl methyltriphenylphosphonium
iodide (3.0 g, 4.8 mmoles) and anhydrous THF (15 ml). The suspension was cooled to
-20
°C and a 1.55 M solution of n-butyllithium (3.1 ml, 4.8 mmoles) was added dropwise,
while maintaining an internal reaction temperature of -20
°C. The suspension became a red solution and stirring was continued 1 hour more at
0
°C. The reaction mixture was chilled to -25
°C and a solution of 1-methyl-imidazole-2-carboxaldehyde (525 mg, 4.8 mmoles) in THF.
(10 ml) was added dropwise over 5 minutes. The reaction mixture was allowed to warm
to room temperature and stir for 12 hours. It was then cooled to 0°C and water (1.0
ml) added. It was further stirred for hour whereupon the solvent was removed in vacuo
to afford the crude product. The crude product was dissolved in ethyl ether (20 ml)
and water (20 ml). The layers were partitioned and separated. The organic phase was
washed with water (2 x 20 ml), dried over MgS0
4, suction filtered, and the filtrate concentrated in vacuo to yield a crude yellow
oil. Further purification was achieved by high performance liquid chromatography to
produce approximately a 1:1 ratio of ci-s and trans-isomers of 1-(5-benzyloxy-2,3-dihydrobenzofuran-6-yl)-2-(1-methyl-imidazol-2-yl)ethene
(600 mg, 38%).
Step G: Preparation of 6-(2-(1-methylimidazol-2-yl)-ethyl)-5-hydroxy-2,3-dihydrobenzofuran
[0082] Approximately a 1:1 ratio of cis and trans isomers of 1-(5-benzyloxy-2,3-dihydrobenzofuran-6-yl)-2-(l-methylimidazol-2-yl)ethene
(104 mg, 0.3 mmoles) was hydrogenated in ethyl alcohol (15 ml) at room temperature
using 10% Pd/C (15 mg) as a catalyst which was removed by suction filtration of the
reaction mixture through a bed of celite. The catalyst bed was washed with ethyl alcohol
(2 x 10 ml) and the filtrate was evaporated in vacuo to afford a white solid. Recrystallization
from methlene chloride/n-hexane produced 6-(2-(1-methylimidazol-2-yl)ethyl)-5-hydroxy-2,3-dihydrobenzofuran
as fine white crystals (60 mg, 79%). m.p. 190-191
°C.
EXAMPLE 4
5-Hydroxy-2,3-dihydro-6-(2-(2-thienyl)ethyl)-benzofuran
Step A: Preparation of 5-acetoxy-2,3-dihydrobenzofuran-6-carboxaldehyde
[0083] A solution of 5-hydroxy-2,3-dihydrobenzofuran-6-carboxaldehyde (5.0 g, 0.030 mol)
in pyridine (10 ml) was cooled to an internal temperature of -5°C. Acetic anhydride
(3.2 g, 0.03 mol) was added dropwise. The cooling bath was removed and the mixture
was allowed to stir under nitrogen for 18 hours. The reaction was quenched into water
(50 ml) at which time the product crystallized and was collected by filtration. The
product was dissolved in methylene chloride (100 ml) and was washed with water (25
ml), saturated sodium bicarbonate (25 ml), saturated sodium chloride (25 ml), dried
(MgS0
4) and concentrated to a dark oil which solidified on standing. The product was ground,
washed with ethyl ether and dried to afford 5-acetoxy-3,4-dihydrobenzofuran-6-carboxaldehyde
(4.6 g, 74%). m.p. 68-70
°C.
Step B: Preparation of (2-thienyl)methyl triphenylphosphonium bromide
[0084] A mixture of 2-methylthiophene (10 g, 0.10 mol) and N-bromosuccinimide (18 g, 0.10
mol) in carbon tetrachloride (100 ml) was heated to reflux under nitrogen. Benzoyl
peroxide (50 mg) was added and the mixture was refluxed for 3 hours. After cooling
to room temperature the reaction was filtered and concentrated to a dark oil. The
crude 2-bromomethylthiophene and triphenylphosphine (29 g, 0.011 mol) were dissolved
in tetrahydrofuran (170 ml) under nitrogen and heated to reflux for 4 hours and then
cooled to room temperature for precipitation. The product was collected by filtration,
washed with ethyl ether (4 x 15 ml) and dried to afford (2-thienyl)methyl triphenylphosphonium
bromide (35 g, 80%i). m.p. 250
°C.
Step C: Preparation of 1-(5-acetoxy-2,3-dihydrobenzofuran-6-yl)-2-(2-thienyl)ethene
(cis- and trans-isomers)
[0085] A mixture of (2-thienyl)methyl triphosphonium bromide (22 g, 0.054 mol) in tetrahydrofuran
(200 ml) was cooled to an internal temperature of 8
°C under nitrogen and a solution of n-butyllithium (1.55 M in hexane, 33 ml, 5.5 mol)
was added dropwise. The resulting mixture was stirred for 10 minutes then 5-ace- toxy-2,3-dihydrobenzofuran-6-carboxaldehyde
(7.0 g, 0.034 mol) was added portionwise. The ice bath was removed and the reaction
was allowed to stir for 3 days. After filtration and concentration the crude product
was purified by chromatography over silica gel (hexane/ethyl acetate, 80/20 as eluent)
to afford a 1:1 mixture of cis- and trans-isomers of 1-(5-acetoxy-2,3-dihydrobenzofuran-6-yl)-2-(2-thienyl)ethene
(0.55 g, 39%).
Step D: Preparation of 5-Hydroxy-2,3-dihydro-6-(2-(2-thienyl)-ethyl-benzofuran
[0086] A mixture of 1-(5-acetoxy-2,3-dihydrobenzofuran-6-yl)-2-(2-thienyl)ethene (0.55 g,
0.0019 mol), in ethanol (20 ml) and 12 N HCI (0.5 ml) was hydrogenated at 40 psi using
10% Pd/C (0.55 g) as catalyst. After filtration and concentration the crude 5-acetoxy-6-(2-(2-thienyl)ethyl)-2,3-dihydrobenzofuran
was dissolved in methylene chloride (20 ml) and washed with saturated sodium bicarbonate
(2 x 10 ml), saturated sodium chloride (10 ml) and concentrated. The resulting yellow
oil was dissolved in ethanol (10 ml) and 50% NaOH (0.2 ml). The mixture was allowed
to stir for ½ hour at room temperature and was concentrated. The crude product was
dissolved in methylene chloride (20 ml) and washed with 10% acetic acid (10 ml), saturated
sodium carbonate (10 ml), saturated sodium chloride (10 ml). The combined organic
layers were dried (MgS0
4), and concentrated to a dark oil. Purification by chromatography over silica gel
(hexane/ethyl acetate, 90/10, as eluent) afforded 5-hydroxy-6-(2-(2-thienyl)ethyl)-2,3-dihydrobenzofuran
(66 mg, 13%). m.p. 79-85
°C.
EXAMPLE 5
6-(2-(2,2-diphenyl)ethyl)-5-hydroxy-2,3-dihydrobenzofuran
[0087] A mixture of (5-benzyloxy-2,3-dihydro-benzofuran-6-yl)methyl triphenylphosphine iodide
(2.0 g, 0.0033 mol) in tetrahydrofuran (20 ml) was cooled to an internal temperature
of 5
°C under nitrogen and a solution of n-butyllithium (1.55 M in hexane, 1.9 ml, 0.0030
mol) was added dropwise. The resulting mixture was stirred for 10 minutes, then benzophenone
(0.47 g, 0.0030 mol) was added portionwise. The ice bath was removed and the reaction
was allowed to stir for 18 hours, then heated to reflux for 4 hours. The reaction
mixture was concentrated to a dark oil which was dissolved in ethyl acetate (20 ml),
washed with water (10 ml), saturated sodium chloride (10 ml). The combined organic
layers were dried (MgS0
4), concentrated, then chromatographed over silica gel (hexane/ethyl acetate, 90/10,
an eluent) to afford 1-(5-benzyloxy-2,3-dihydrobenzofuran-6-yl)-2,2-diphenyl-ethene
(0.27 g, 22%).
[0088] The material was suspended in ethanol (10 ml) and 12 M HCI (.03 ml) and hydrogenated
at 40 psi using 10% Pd/C as catalyst. After filtration and concentration the crude
product was purified by chromatography over silica gel (hexane/ethyl acetate, 90/10,
an eluent) to afford 6-(2-(2,2-diphenyl)ethyl)-5-hydroxy-2,3-dihydro-benzofuran (0.12
g, 13%). m.p. 153-157
°C.